Change Rectangle.operator== to compare right/bottom instead of width/height.

sdk/lib/math/rectangle.dart

Index: sdk/lib/math/rectangle.dart
diff --git a/sdk/lib/math/rectangle.dart b/sdk/lib/math/rectangle.dart
index e0a3b9870fce43a6644f1baa255ffe8f6ca82ac0..0673b0d2740f37429bf34ba023938d4c714a5692 100644
--- a/sdk/lib/math/rectangle.dart
+++ b/sdk/lib/math/rectangle.dart
@@ -36,12 +36,12 @@ abstract class _RectangleBase<T extends num> {
 
   bool operator ==(other) {
     if (other is !Rectangle) return false;
-    return left == other.left && top == other.top && width == other.width &&
-        height == other.height;
+    return left == other.left && top == other.top && right == other.right &&
+        bottom == other.bottom;
   }
 
   int get hashCode => _JenkinsSmiHash.hash4(left.hashCode, top.hashCode,
-      width.hashCode, height.hashCode);
+      right.hashCode, bottom.hashCode);
 
   /**
    * Computes the intersection of `this` and [other].